Current virtual image displayers, such as the traditional HMD (head mounted displayer), project by optic reflection and refraction, e.g. the semi-reflection and refraction combined optic virtual image displayer introduced in Patent 200710176478.X. The virtual image is formed on an image forming piece after split on a polarizing sheet; at this time, the image forming focus length (distance from the polarizing sheet to the image forming piece) is long; the image on the image forming piece is formed by two overlapped semi-real and semi-virtual images on the visual focus length (distance from eyes to the polarizing sheet), the definition is poor; the image on the image forming piece will be gradually deformed with magnifying, as it is a basic principle of geometrical optics. And meanwhile by the setting of image forming piece, the visual focus length axis of the virtual image displayer is long, and the displayer appearance and dimensions are influenced. When a displayer with projecting system is being designed according to the geometrical optics, multi-layer magnifying is the usual way to solve the deformation of projected image, the image deformation is minimized by magnifying and regulating the scattering angle in each layer, the light path axis of such a displayer is prolonged, and a combination of many lens are used, and the dimensions are highly enlarged.